A mix asphalt is generally a combination of asphalt and stone mineral aggregates in exact proportions. The relative proportions of these minerals determine the physical properties of the mix asphalt in question and, possibly, the performance thereof as a finished mix for a determined use.
The mix asphalt must be durable, i.e., it must be resistant to actions such as the detachment of the asphalt film from the aggregate due to the effects of the water, of the abrasion from traffic, etc. Likewise, it must be resistant to traffic stresses through its stability. Furthermore, a mix asphalt must be impermeable so that its components are not under the direct action of atmospheric agents, and at the same time it must be possible to work on it to allow its easy placement and compaction on the ground. Each of these are desirable properties of mix asphalts.
The mentioned mix asphalts can be made in plants by means of suitable equipment for performing this task. According to the properties of these mix asphalts, as well as their layer thicknesses, it is considered that they provide structural capacity to the pavement on which they are arranged.
Thus, roads and pavements are currently made with mix asphalts. The construction, maintenance and use of the mentioned roads and pavements has an enormous impact on the environment. This is why the production and application of reduced-temperature mix asphalts is an enormous progress used today, given that it reduced the mentioned impact to a great extent.
Therefore, the industry has recently focused on reducing the temperatures for the production and application of mix asphalts.
The production and application of mix asphalts under hot conditions typically requires the materials to be heated between 135° C. and 180° C. This temperature is partly dictated by the viscosity of the asphalt binder and is necessary for assuring a homogeneous and complete coating of the aggregates by the asphalt.
Said limitations must be taken into account when considering the possibilities of reducing the temperatures for the production and application of the mentioned mix asphalts together with the need to assure the mechanical properties of the new pavement.
There are several options for achieving the previous objectives by using mix asphalts at significantly reduced temperatures, one of which is to use warm mix asphalts the production and application of which requires the materials to be heated between 60° C. and 100° C., such that a considerable saving in energy is achieved, as well as considerable reduction of emissions to the environment (CO2, SOx, NOx, volatile organic compounds, dust, etc.).
Known plants which currently use semi-hot mix asphalt production processes have drawbacks, such as for example that they are fixed and non-versatile installations, the minimum temperatures obtained being 130° C., such that only asphalt products of a determined type can be obtained with them. Furthermore, these known plants have the drawback of not being capable of reducing this temperature due to process limitations, and reaching the 60-100° C. which are achieved with the plants object of the invention, which entails errors and deficiencies in the operation thereof.
The present invention is aimed at solving the aforementioned drawbacks.